Method and apparatus for searching for device by using bluetooth low energy (LE) technology

ABSTRACT

Disclosed herein are a method and apparatus for discovering an adjacent device in a wireless communication system using Bluetooth low energy (LE). In particular, the method performed by a first device includes recognizing an advertising channel in which interference exists among three advertising channels constituting a first advertising channel set, transmitting a control message instructing application of a protected mode to a second device, when the advertising channel in which interference exists is recognized, the protected mode indicating a mode for transmitting and receiving a message using a second advertising channel set updated from the first advertising channel set in a non-connection state, and receiving an advertisement message from the second device through the second advertising channel set.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT/KR2018/003186 filed onMar. 19, 2018, which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Nos. 62/472,604 filed on Mar. 17, 2017;62/488,068 filed on Apr. 21, 2017; and 62/507,743 filed on May 17, 2017,all of which are hereby expressly incorporated by reference into thepresent application.

TECHNICAL FIELD

The present disclosure relates to a method and apparatus for discoveringa device using Bluetooth, a short-range technology, in a wirelesscommunication system, and more particularly, a method and apparatus forprotecting an advertising channel used for device discovery usingBluetooth low energy (BLE) technology.

BACKGROUND ART

Bluetooth is an NFC technology standard allowing various devices to bewirelessly connected in a near field to exchange data. In a case inwhich two devices intend to perform wireless communication usingBluetooth communication, a user may perform a procedure for discoveringa Bluetooth device with which he or she wants to communicate andrequesting a connection.

Here, the user may discover a Bluetooth device according to a Bluetoothcommunication method intended to be used using the Bluetooth device, andsubsequently perform a connection.

The Bluetooth communication method may be classified as a BR/EDR methodand an LE method. The BR/EDR method may be termed Bluetooth Classic. TheBluetooth Classic method includes a Bluetooth technology led fromBluetooth 1.0 and a Bluetooth technology using an enhanced data rate(EDR) supported by Bluetooth 2.0 or a subsequent version.

A Bluetooth low energy (LE) technology applied, starting from Bluetooth4.0, may stably provide information of hundreds of kilobytes (KB) at lowpower consumption. Such a Bluetooth low energy technology allows devicesto exchange information with each other by utilizing an attributeprotocol. The Bluetooth LE method may reduce energy consumption byreducing overhead of a header and simplifying an operation.

Among the Bluetooth devices, some products do not have a display or auser interface. Complexity of connection, management, control, anddisconnection among various types of Bluetooth devices and Bluetoothdevice employing similar technologies has increased.

Bluetooth supports a high speed at relatively low power consumption andat relatively low cost. However, since a transmission distance thereofis 100 m at the maximum, and thus, Bluetooth is appropriately usedwithin a limited space.

DISCLOSURE Technical Problem

In the current BLE technology, advertisement using channels other than aprimary advertising channel set is not possible. Therefore, in order toperform advertisement using four advertising channels, a new link layerprotocol and a new host controller interface (HCI) are required.

In case where an advertising channel set is to be modified according tothe presence of interference, it is necessary to share the correspondinginformation between an advertiser and a scanner, but the aforementionedtechnology cannot be implemented in the case of using an advertisementPDU defined in the existing BLE technology.

An embodiment of the present disclosure proposes a link layer protocoland an HCI to solve such a problem and to avoid interference occurringat a band boundary.

The technical problems to be achieved by the present disclosure are notlimited to the above-mentioned technical problems and any othertechnical problems that are not mentioned may be clearly understood bythose skilled in the art to which the present disclosure pertains fromthe following descriptions.

Technical Solution

In an aspect, a method for discovering an adjacent device in a wirelesscommunication system using Bluetooth low energy (LE), which is performedby a first device, includes: recognizing an advertising channel in whichinterference exists among three advertising channels constituting afirst advertising channel set; transmitting a control messageinstructing application of a protected mode to a second device, when theadvertising channel in which interference exists is recognized, theprotected mode indicating a mode for transmitting and receiving amessage using a second advertising channel set updated from the firstadvertising channel set in a non-connection state; and receiving anadvertisement message from the second device through the secondadvertising channel set.

Preferably, the second advertising channel set may be updated toadditionally include at least one advertising channel in addition to thethree advertising channels constituting the first advertising channelset.

Preferably, the control message may include at least one of operationcode information instructing updating of the first advertising channelset, index information of the additionally included advertising channel,or number information of the advertising channels included in the secondadvertising channel set.

Preferably, the second advertising channel set may be updated to replacethe advertising channel in which interference exists with a specificchannel among data channels used for transmitting and receiving data.

Preferably, the control message may include at least one of operationcode information instructing updating of the first advertising channelset, index information of the advertising channel in which interferenceexists, or index information of the replacing specific channel.

Preferably, the method may further include: transmitting a requestmessage requesting information related to updating of the firstadvertising channel set to the second device; and receiving a responsemessage including the information related to updating in response to therequest message from the second device.

Preferably, the information related to updating may include informationrelated to an auxiliary advertising channel available in the seconddevice or information related to an advertising channel set available inthe second device.

Preferably, the first device and the second device may form a meshnetwork.

Preferably, the control message may include at least one of operationcode information indicating updating of the first advertising channelset, index information of the advertising channel in which interferenceexists, an index information of an advertising channel added to thefirst advertising channel set, number information of the advertisingchannels included in the second advertising channel set, or hop countinformation for limiting a maximum hop number.

Preferably, the control message may be dropped or transmitted to one ormore adjacent devices by the second device according to the hop countvalue.

In another aspect, a first device for discovering an adjacent device ina wireless communication system using Bluetooth low energy (LE)includes: a communication unit communicating with an external devicewirelessly or wiredly; and a processor functionally connected to thecommunication unit, wherein the processor recognizes an advertisingchannel in which interference exists among three advertising channelsconstituting a first advertising channel set, transmits a controlmessage instructing application of a protected mode to a second device,when the advertising channel in which interference exists is recognized,the protected mode indicating a mode for transmitting and receiving amessage using a second advertising channel set updated from the firstadvertising channel set in a non-connection state, and receives anadvertisement message from the second device through the secondadvertising channel set.

Preferably, the second advertising channel set may be updated toadditionally include at least one advertising channel in addition to thethree advertising channels constituting the first advertising channelset.

Preferably, the control message may include at least one of operationcode information instructing updating of the first advertising channelset, index information of the additionally included advertising channel,or number information of the advertising channels included in the secondadvertising channel set.

Preferably, the second advertising channel set may be updated to replacethe advertising channel in which interference exists with a specificchannel among data channels used for transmitting and receiving data.

Preferably, the control message may include at least one of operationcode information instructing updating of the first advertising channelset, index information of the advertising channel in which interferenceexists, or index information of the replacing specific channel.

Advantageous Effects

According to an embodiment of the present disclosure, by additionallyincluding another advertising channel to a primary advertising channelset used in the existing BLE technology, a degradation ofadvertisement/scanning efficiency may be prevented despite the presenceof interference occurring at the edge of a BLE frequency band andreliability of discovery of a BLE device may be increased.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present disclosure are notlimited to what has been particularly described hereinabove and otheradvantages of the present disclosure will be more clearly understood bya person skilled in the art to which the present disclosure pertains,from the following detailed description.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating an example of a wirelesscommunication system using the Bluetooth low energy (BLE) technologyproposed in the present disclosure.

FIG. 2 shows an example of an internal block diagram of a device thatmay implement the methods proposed in the present disclosure.

FIG. 3 shows an example of a BLE topology.

FIG. 4 is a diagram illustrating an example of a Bluetooth communicationarchitecture to which the methods proposed in the present disclosure maybe applied.

FIG. 5 is a diagram illustrating an example of a structure of a genericattribute profile) of BLE.

FIG. 6 is a flowchart illustrating a method of forming a connectionusing BLE between devices.

FIG. 7 is a diagram illustrating a frequency band of a BLE advertisingchannel, as an embodiment to which the present disclosure may beapplied.

FIG. 8 is a diagram illustrating a frequency band of an advertisingchannel, as an embodiment to which the present disclosure may beapplied.

FIG. 9 is a diagram illustrating an advertising channel set whichadditionally uses an advertising channel, as an embodiment to which thepresent disclosure is applied.

FIG. 10 is a diagram illustrating a generic access profile (GAP) timeraccording to the use of an additional advertising channel, as anembodiment to which the present disclosure is applied.

FIG. 11 is a diagram illustrating an advertising channel setadditionally using an advertising channel, as an embodiment to which thepresent disclosure is applied.

FIG. 12 shows an example of an advertising event according to a modifiedadvertising channel set, as an embodiment to which the presentdisclosure is applied.

FIG. 13 shows an example of a method of performing an advertisementusing four fixed channels, as an embodiment to which the presentdisclosure is applied.

FIG. 14 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

FIG. 15 is a diagram illustrating a format of an advertising packetindicating whether to apply a protected mode of an advertising channel,as an embodiment to which the present disclosure is applied.

FIG. 16 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

FIG. 17 is a diagram illustrating an example of a format of a controlmessage indicating whether to apply a protected mode of an advertisingchannel, as an embodiment to which the present disclosure is applied.

FIG. 18 is a flowchart illustrating a method of modifying an advertisingchannel set through a negotiation procedure according to whetherinterference exists in an advertising channel, as an embodiment to whichthe present disclosure is applied.

FIG. 19 is a diagram illustrating a format of a control messageindicating whether to apply a protected mode of an advertising channel,as an embodiment to which the present disclosure is applied.

FIG. 20 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

FIG. 21 is a diagram illustrating an example of a format of anadvertising packet indicating whether to apply a protected mode of anadvertising channel, as an embodiment to which the present disclosure isapplied.

FIG. 22 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether an interference exists in anadvertising channel, as an embodiment to which the present disclosure isapplied.

FIG. 23 is a diagram illustrating an example of a format of controlinformation including advertising channel information related toapplication of a protected mode of an advertising channel, as anembodiment to which the present disclosure is applied.

FIG. 24 is a flowchart illustrating a method of modifying an advertisingchannel set through a negotiation procedure according to whetherinterference exists in an advertising channel, as an embodiment to whichthe present disclosure is applied.

FIG. 25 is a diagram illustrating a method of protecting an advertisingchannel in a mesh network, as an embodiment to which the presentdisclosure is applied.

FIG. 26 is a diagram illustrating an example of a method of releasingprotection of an advertising channel in a mesh network, as an embodimentto which the present disclosure is applied.

FIGS. 27 and 28 illustrate a method of applying a protected mode of anadvertising channel according to an interference environment for eachregion in the case of establishing a wide area mesh network, as anembodiment to which the present disclosure is applied.

FIGS. 29 and 30 are flowcharts illustrating a method of modifying ascanning mode according to the presence or absence of interference, asan embodiment to which the present disclosure may be applied.

FIG. 31 is a diagram illustrating an operation between a new device anda legacy device when a protected mode of an advertising channel isapplied, as an embodiment to which the present disclosure may beapplied.

FIG. 32 is a diagram illustrating a method of applying a protected modeof an advertising channel, as an embodiment to which the presentdisclosure may be applied.

FIG. 33 is a diagram illustrating a method of periodically indicatingwhether a protected mode of an advertising channel is applied, as anembodiment to which the present disclosure may be applied.

FIG. 34 is a diagram illustrating a method for periodically indicatingwhether to apply a protected mode of an advertising channel, as anembodiment to which the present disclosure may be applied.

FIG. 35 is a diagram illustrating a method of applying a protected modeof an advertising channel according to an interference environment foreach region in the case of establishing a wide area mesh network, as anembodiment to which the present disclosure may be applied.

FIG. 36 illustrates an example of a method for protecting an advertisingchannel, as an embodiment to which the present disclosure is applied.

MODE FOR INVENTION

The aforementioned objects, features and advantages of the presentinvention will become more apparent through the following detaileddescription with respect to the accompanying drawings. Hereinafter, theembodiments of the present invention will be described with reference tothe accompanying drawings, in which like numbers refer to like elementsthroughout the specification. In describing the present invention, adetailed description of known techniques associated with the presentinvention unnecessarily obscure the gist of the present invention, it isdetermined that the detailed description thereof will be omitted.

Hereinafter, a terminal related to the present disclosure will bedescribed in detail with reference to the accompanying drawings. In thefollowing description, usage of suffixes such as ‘module’, ‘part’ or‘unit’ used for referring to elements is given merely to facilitateexplanation of the present disclosure, without having any significantmeaning by itself.

FIG. 1 is a schematic view illustrating an example of a wirelesscommunication system using a Bluetooth low energy technology to whichthe present disclosure is applicable.

A wireless communication system 100 includes at least one server device120 and at least one client device 110.

The server device and the client device perform Bluetooth communicationusing a Bluetooth low energy (BLE) technology.

First, compared with a Bluetooth basic rate/enhanced data rate (BR/EDR),the BLE technology has a relatively small duty cycle, may be produced atlow cost, and significantly reduce power consumption through a low datarate, and thus, it may operate a year or longer when a coin cell batteryis used.

Also, in the BLE technology, an inter-device connection procedure issimplified and a packet size is designed to be small compared with theBluetooth BR/EDR technology.

In the BLE technology, (1) the number of RF channels is forty, (2) adata rate supports 1 Mbps, (3) topology has a scatternet structure, (4)latency is 3 ms, (5) a maximum current is 15 mA or lower, (6) outputpower is 10 mW (10 dBm) or less, and (7) the BLE technology is commonlyused in applications such as a clock, sports, healthcare, sensors,device control, and the like.

The server device 120 may operate as a client device in a relationshipwith other device, and the client device may operate as a server devicein a relationship with other device. That is, in the BLE communicationsystem, any one device may operate as a server device or a clientdevice, or may operate as both a server device and a client device ifnecessary.

The server device 120 may also be called as data service device, slavedevice, slave, server, conductor, host device, gateway, sensing device,monitoring device, first device, or the like, and the client device 110may also be called as master device, master, client, member, sensordevice, sink device, collector, second device, third device, and thelike.

The server device and the client device correspond to major componentsof the wireless communication system, and the wireless communicationsystem may include components other than the server device and theclient device.

The server device refers to a device which receives data from the clientdevice and provides data to the client device in response when acorresponding request is received from the client device, through directcommunication with the client device.

Also, in order to provide data information to the client device, theserver device sends a notification message or an indication message tothe client device in order to provide data information to the clientdevice. Also, the server device receives a confirmation messagecorresponding to the indication message from the client device.

Also, in the process of transmitting and receiving notification,indication, and confirmation messages to and from the client device, theserver device may provide data information to a user through a displayunit or may receive a request input from the user through a user inputinterface.

Also, in the process of transmitting and receiving message to and fromthe client device, the server device may read data from a memory unit ormay write new data to the corresponding memory unit.

Also, the single server device may be connected with a plurality ofclient devices, and may be easily re-connected with client devices usingbonding information.

The client device 120 refers to a device which requests data informationand data transmission from the server device.

The client device receives data through a notification message or anindication message from the server device, and when an indicationmessage is received from the server device, the client device sends anacknowledgement message in response to the indication message.

Similarly, in the process of transmitting and receiving messages to andfrom the server device, the client device may also provide informationto the user through a display unit or may receive an input from the userthrough a user input interface.

Also, in the process of transmitting and receiving messages with theserver device, the client device may read data from a memory unit or maywrite new data to the corresponding memory unit.

Hardware components such as the display units, the user inputinterfaces, and the memory units of the server device and the clientdevice will be described in detail with reference to FIG. 2.

Also, the wireless communication system may configure personal areanetworking (PAN) through the Bluetooth technology. For example, in thewireless communication system, a private piconet may be establishedbetween devices to quickly and safely exchange files, documents, and thelike.

In addition, there are a number of devices that measure physicalactivities of human beings using a specific device, but there is nodevice that transmits measured data via Bluetooth to show a specificdata value to a user.

Therefore, in order to solve this problem, the present disclosureproposes a method of measuring a physical activity of a human being,transmitting and processing the measured data through Bluetooth LE, andproviding the same to a user.

FIG. 2 shows an example of an internal block diagram of a device thatmay implement the methods proposed in the present disclosure.

As shown in FIG. 2, a server device includes an output unit (displayunit) 111, an input unit (user input interface) 112, a power supply unit113, a processor, a memory 115, a Bluetooth interface 116, anothercommunication interface 117, and a communication unit (or a transceiverunit 118).

The output unit 111, the input unit 112, the power supply unit 113, theprocessor 114, the memory 115, the Bluetooth interface 116, the othercommunication interface 117, and the communication unit 118 arefunctionally connected to each other to carry out the method proposed inthe present disclosure.

In addition, a client device includes an output unit (display unit) 121,an input unit (user Input Interface) 122, a power supply unit 123, aprocessor 124, a memory 125, a Bluetooth interface 126, and acommunication unit (or a transceiver unit 127).

The output unit 121, the input unit 122, the power supply unit 123, theprocessor 124, the memory 125, the Bluetooth interface 126, and thecommunication unit 127 are functionally connected to each other toperform the methods proposed in the present disclosure.

The Bluetooth interface 116 or 126 refers to units (or modules) capableof transmitting requests/responses, commands, notifications,instructions/confirmation messages, or the like between devices usingBluetooth technology.

The memory 115 or 125, as a unit implemented in various types ofdevices, refer to units in which various types of data are stored.

The processor 114 or 124 refer to a module that controls an overalloperation of the server device or the client device, and control torequest transmission of a message and process a received message througha Bluetooth interface and another communication interface.

The processor 114 or 124 may be represented by a controller, a controlunit, or the like.

The processor 114 or 124 may include an application-specific integratedcircuit (ASIC), another chipset, a logic circuit, and/or a dataprocessing device.

The processor 114 or 124 controls the communication unit to receive anadvertisement message from the server device, controls the communicationunit to transmit a scan request message to the server device and receivea scan response message as a response to the scan request from theserver device, and controls the communication unit to transmit aconnection request message to the server device to establish Bluetoothconnection with the server device.

In addition, the processor 114 or 124 may control the communication unitto read or write data from or into the server device using an attributeprotocol after the BLE connection is established through a connectionprocedure.

The memory 115 or 125 may include a read-only memory (ROM), a randomaccess memory (RAM), a flash memory, a memory card, a storage medium,and/or another storage device.

The communication unit 118 or 127 may include a baseband circuit forprocessing a radio signal. When the embodiment is implemented insoftware, the above-described technique may be implemented as a module(process, function, etc.) for performing the above-described function.The module may be stored in a memory and executed by a processor.

The memory 115 or 125 may be within or outside the processor 114 or 124and may be connected to the processor 114 or 124 by various well-knownmeans.

The output unt 111 or 121 refers to a module for providing device statusinformation and message exchange information to a user through a screen.

The power supply unit 113 or 123 refers to a module for supplying powerrequired for an operation of each component by receiving external powerand internal power under the control of the controller.

As discussed above, the BLE technology has a small duty cycle and maysignificantly reduce power consumption through a low data rate, so thatthe power supply unit may supply power for the operation of eachcomponent even with a low output power (10 mW (10 dBm) or less).

The input unit 112 or 122 refers to a module that provide a user inputto the controller like a screen button so that the user may control anoperation of the device.

FIG. 3 shows an example of a BLE topology.

Referring to FIG. 3, device A corresponds to a master in a piconet(piconet A, shaded portion) having device B and device C as slaves.

Here, the piconet refers to an aggregation of a plurality of devicesoccupying a shared physical channel in which one of a plurality ofdevices is a master and the other devices are connected to the masterdevice.

The BLE slave does not share a common physical channel with the master.Each slave communicates with the master through a separate physicalchannel. There is another piconet (piconet F) having master device F andslave device G.

Device K is in scatternet K. Here, the scatternet refers to a group ofpiconets in which there is a connection between different piconets.

The device K is a master of device L and a slave of device M.

Device O is also in scatternet O. The device O is a slave of device Pand a slave of device Q.

As shown in FIG. 3, there are five different device groups.

1. Device D is an advertiser and device A is an initiator (group D).

2. Device E is a scanner and device C is an advertiser (group C).

3. Device H is an advertiser and devices I and J are scanners (group H).

4. Device K is also an advertiser and device N is an initiator (groupK).

5. Device R is an advertiser and device O is an initiator (group R).

Devices A and B use one BLE piconet physical channel.

Devices A and C use another BLE piconet physical channel.

In group D, device D advertises using an advertising event connectableon an advertising physical channel, and device A is an initiator. DeviceA may establish a connection with device D and add a device to piconetA.

In group C, device C advertises on an advertising physical channel usinga certain type of advertising event captured by scanner device E.

Group D and Group C may use different advertising physical channels oruse different times to avoid a collision.

Piconet F has one physical channel. Devices F and G use one BLE piconetphysical channel. Device F is a master and device G is a slave.

Group H has one physical channel. Devices H, I and J use one BLEadvertising physical channel. Device H is an advertiser and devices Iand J are scanners.

In scatternet K, devices K and L use one BLE piconet physical channel.

Devices K and M use another BLE piconet physical channel.

In group K, device K advertises using an advertising event connectableon an advertising physical channel, and device N is an initiator. DeviceN may form a connection with device K. Here, device K is a slave of twodevices and also is a master of one device.

In scatternet O, devices O and P use one BLE piconet physical channel.Devices O and Q use another BLE piconet physical channel.

In group R, device R advertises using an advertising event connectableon an advertising physical channel, and device O is an initiator. DeviceO may form a connection with device R. Here, device a is a slave of twodevices and also is a master of one device.

FIG. 4 is a diagram illustrating an example of a Bluetooth communicationarchitecture to which the methods proposed in the present disclosure maybe applied.

Referring to FIG. 4, (a) of FIG. 4 shows an example of a protocol stackof Bluetooth basic rate (BR)/enhanced data rate (EDR), and (b) shows aprotocol stack of Bluetooth low energy (BLE).

Specifically, as shown in (a) of FIG. 4, the Bluetooth BR/EDR protocolstack includes an upper controller stack 10 and a lower host stack 20with respect to a host controller interface (HCI) 18.

The host stack (or host module) 20 refers to a wireless transceivermodule receiving a 2.4 GHz Bluetooth signal and hardware fortransmitting or receiving a Bluetooth packet, and is connected to aBluetooth module which is the controller stack 10 to control theBluetooth module and perform an operation.

The host stack 20 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager layer 16.

The BR/EDR PHY layer 12 is a layer for transmitting/receiving a 2.4 GHzradio signal and may transmit data by hopping 79 RF channels in the caseof using Gaussian frequency shift Keying (GFSK) modulation.

The BR/EDR baseband layer 14 plays a role of transmitting a digitalsignal, selects a channel sequence which hops 1400 times per second, andtransmits a 625-us length time slot for each channel.

The link manager layer 16 controls an overall operation (link setup,control, security) of the Bluetooth connection by utilizing a linkmanager protocol (LMP).

The link manager layer 16 may perform the following functions.

-   -   ACL/SCO logical transport, logical link setup and control.    -   Detach: It stops connection and informs a counterpart device of        a reason for stopping.    -   Power control and role switch.    -   It performs security (authentication, pairing, encryption)        functions.

The host controller interface layer 18 provides an interface between thehost module and the controller module so that a host may providecommands and data to the controller, and allow the controller to provideevents and data to the host.

The host stack (or host module) 20 includes a logical link control andadaptation protocol (L2CAP) 21, a security manager (SM) 22, an attributeprotocol 23, a generic attribute profile (GATT) 24, a generic accessprofile (GAP) 25, and a BR/EDR profile 26.

The logical link control and adaptation protocol (L2CAP) 21 may provideone bidirectional channel for transmitting data to a specific protocolor profile.

The L2CAP 21 may multiplex various protocols, profiles, and the likeprovided by a higher layer of Bluetooth.

The L2CAP of the Bluetooth BR/EDR uses dynamic channel, supportsprotocol service multiplexer, retransmission, streaming mode, andprovides segmentation, reassembly, per-channel flow control, and errorcontrol.

The security manager (SM) 22 is a protocol for authenticating a deviceand providing a key distribution.

The GATT 24 may be operable as a protocol describing how the attributeprotocol 23 is used when services are configured. For example, the GATT24 may be operable to define how ATT attributes are grouped togetherinto services, and may be operable to describe features associated withthe services.

Thus, the GATT 24 and the attribute protocol (ATT) 23 may use featuresto describe a state and services of a device, how features relate toeach other, and how they are used.

The attribute protocol 23 and the profiles 26 define a service (profile)using Bluetooth BR/EDR and an application protocol for transmitting andreceiving these data, and the GAP 25 defines a method of discovering andconnecting a device and providing information to the user, and provideprivacy.

As shown in (b) of FIG. 4, the Bluetooth LE protocol stack includes acontroller stack 30 operable to process timing-critical wireless deviceinterface and a host stack 40 operable to process high level data.

First, the controller stack 30 may be implemented by using acommunication module that may include a Bluetooth wireless device, forexample, a processor module that may include a processing device such asa microprocessor.

The host stack may be implemented as part of an OS operated on aprocessor module or may be implemented as instantiation of a package onthe OS.

In some examples, the controller stack and the host stack may beoperated or executed on the same processing device within a processormodule.

The controller stack 30 includes a physical layer (PHY) 32, a link layer(LL) 34, and a host controller interface (HCI) 36.

The physical layer (PHY) (wireless transceiver module 32), a layer fortransmitting and receiving a 2.4 GHz wireless signal, uses a Gaussianfrequency shift keying (GFSK) modulation and a frequency hoppingtechnique including forty RF channels.

The link layer 34 serving to transmit or receive a Bluetooth packetprovides a function of generating a connection between devices afterperforming an advertising and scanning function using three advertisingchannels, and exchanging data packets of a maximum of 257 bytes throughthirty-seven data channels.

The host stack may include a generic access profile (GAP) 40, a logicallink control and adaptation protocol (L2CAP) 41, a security manager (SM)42, an attribute protocol (ATT) 440, a generic attribute profile (GATT)44, a generic access profile 25, and an LT profile 46. However, the hoststack 40 is not limited thereto and may include various protocols andprofiles.

The host stack multiplexes various protocols and profiles provided froma Bluetooth higher position by using the L2CAP.

First, the L2CAP 41 may provide a single two-way channel fortransmitting data to a specific protocol or profile.

The L2CAP 41 may operate to multiplex data between higher layerprotocols, segment and reassemble packages, and manage a multicast datatransmission.

Bluetooth LE uses three fixed channels: one for a signaling channel, onefor a security manager, and one for the attribute protocol.

Meanwhile, BR/EDR uses dynamic channels and supports protocol servicemultiplexer, retransmission, streaming mode, and the like.

The SM 42 is a protocol for certifying a device and providing a keydistribution.

The ATT 43 defines a rule for accessing data of a counterpart device bya server-client structure. The ATT 43 includes six types of messages(request, response, command, notification, indication, and confirmation)as follows.

{circle around (1)} Request and Response message: A request message is amessage for requesting specific information from the client device tothe server device, and the response message is a response message to therequest message, which is a message transmitted from the server deviceto the client device.

{circle around (2)} Command message: It is a message transmitted fromthe client device to the server device in order to indicate a command ofa specific operation. The server device does not transmit a responsewith respect to the command message to the client device.

{circle around (3)} Notification message: It is a message transmittedfrom the server device to the client device in order to notify an event,or the like. The client device does not transmit a confirmation messagewith respect to the notification message to the server device.

{circle around (4)} Indication and confirmation message: It is a messagetransmitted from the server device to the client device in order tonotify an event, or the like. Unlike the notification message, theclient device transmits a confirmation message regarding the indicationmessage to the server device.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

{circle around (1)} Service: It defines a basic operation of a device bya combination of behaviors related to data

{circle around (2)} Include: It defines a relationship between services

{circle around (3)} Characteristics: It is a data value used in a server

{circle around (4)} Behavior: It is a format that may be read by acomputer defined by a UUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

{circle around (1)} Battery: Battery information exchanging method

{circle around (2)} Time: Time information exchanging method

{circle around (3)} FindMe: Provision of alarm service according todistance

{circle around (4)} Proximity: Battery information exchanging method

{circle around (5)} Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack.

When requests are received from all the devices, it is not necessary torespond thereto, and thus, the controller stack may perform control toreduce the number of transmitted requests to reduce power consumption.

An advertising device or scanning device may perform the devicefiltering procedure to limit devices for receiving an advertisingpacket, a scan request or a connection request.

Here, the advertising device refers to a device transmitting anadvertising event, that is, a device performing an advertisement and isalso termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, in a case in which the scanning device receives someadvertising packets from the advertising device, the scanning deviceshould transmit a scan request to the advertising device.

However, in a case in which a device filtering procedure is used so ascan request transmission is not required, the scanning device maydisregard the advertising packets transmitted from the advertisingdevice.

Even in a connection request process, the device filtering procedure maybe used. In a case in which device filtering is used in the connectionrequest process, it is not necessary to transmit a response with respectto the connection request by disregarding the connection request.

Advertising Procedure

The advertising device performs an advertizing procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertizing toward all the devices,rather than broadcast toward a specific device, and all the devices mayscan advertising to make an supplemental information request or aconnection request.

In contrast, directed advertising may make an supplemental informationrequest or a connection request by scanning advertising for only adevice designated as a reception device.

The advertising procedure is used to establish a Bluetooth connectionwith an initiating device nearby.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisingevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising devices transmit responses with respect to thescan requests to the devices which have transmitted the scan requests,through the same advertising physical channels as the advertisingphysical channels in which the scan requests have been received.

Broadcast user data sent as part of advertising packets are dynamicdata, while the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may start advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcasting of user datafrom advertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device. The advertising device transmits ascan response as a response with respect to the scan request, byincluding additional user data which has requested by the scanningdevice through an advertising physical channel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiates a connectionrequest. The scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

Devices available for Bluetooth communication (hereinafter, referred toas “Bluetooth devices”) perform an advertising procedure and a scanningprocedure in order to discover devices located nearby or in order to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice intending to discover other device nearby is termed a discoveringdevice, and listens to discover devices advertising an advertising eventthat may be scanned. A Bluetooth device which may be discovered by otherdevice and available to be used is termed a discoverable device andpositively broadcasts an advertising event such that it may be scannedby other device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical, and requests that, while aspecific Bluetooth device is performing an advertising procedure,another Bluetooth device should perform a scanning procedure.

That is, an advertising procedure may be aimed, and as a result, onlyone device may response to the advertising. After a connectableadvertising event is received from an advertising device, a connectingrequest may be transmitted to the advertising device through anadvertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states, that is, an advertising state, ascanning state, an initiating state, and a connection state, in the BLEtechnology will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the LL listens to an advertising channelindex in a scan window duration. A scan interval is defined as aninterval between start points of two continuous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and cannottransmit any packet.

In the active scanning, the LL performs listening in order to be reliedon an advertising PDU type for requesting advertising PDUs andadvertising device-related supplemental information from the advertisingdevice.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening onadvertising channel indices.

During the initiating state, the LL listens to an advertising channelindex during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary to consider that theconnection should be established at a point in time at which the LLenters the connection state. The only difference between a newlygenerated connection and an already established connection is a LLconnection supervision timeout value.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts a timing of a connectingevent, and the connecting event refers to a point in time at which themaster and the slave are synchronized.

Hereinafter, packets defined in an Bluetooth interface will be brieflydescribed. BLE devices use packets defined as follows.

Packet Format

The LL has only one packet format used for both an advertising channelpacket and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising physical channel, thePDU may be an advertising channel PDU, and when one packet istransmitted in a data physical channel, the PDU may be a data channelPDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 1 below.

TABLE 1 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU

The following advertising channel PDU types are termed advertising PDUsand used in a specific event.

ADV_IND: Connectable undirected advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in an advertising state, andreceived by the LL in a scanning state or in an initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning

PDUs and are used in a state described hereinafter.

SCAN_REQ: Transmitted by the LL in a scanning state and received by theLL in an advertising state.

SCAN_RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may include a message integrity check (MIC) fieldhaving a 16-bit header and payload having various sizes.

The procedures, states, and packet formats in the BLE technologydiscussed above may be applied to perform the methods proposed in thepresent disclosure.

FIG. 5 is a view illustrating an example of a structure of a genericattribute profile (GATT) of Bluetooth low energy.

Referring to FIG. 5, a structure for exchanging profile data ofBluetooth low energy may be looked through.

In detail, the GATT defines a method for exchanging data using a servicebetween Bluetooth LE devices and a characteristic.

In general, a peripheral device (e.g., a sensor device) serves as a GATTserver, and has definition regarding a service and a characteristic.

In order to read or write data, a GATT client sends a data request tothe GATT server, and every operation (transaction) is started by theGATT client and a response is received from the GATT server.

A GATT-based operational structure used in the Bluetooth LE may be avertical structure as illustrated in FIG. 5 based on a profile, aservice, and a characteristic.

The profile includes one or more services, and the services may includeone or more characteristics or other services.

The service serves to divide data into logical units and may include oneor more characteristics or other services, each of the services has a16-bit or 128-bit identifier called a universal unique identifier(UUID)).

The characteristic is the lowermost unit in the GATT-based operationalstructure. The characteristic includes only one data, and has a 16-bitor 128-bit UUID, similar to the service.

The characteristic is defined by values of various types of information,and in order to hold each information, an attribute may be required foreach information. The characteristic may use several continuousattributes.

The attribute has four components and has meanings as follows.

-   -   handle: Address of attribute    -   Type: Type of attribute    -   Value: Value of attribute    -   Permission: Right to access attribute

The present disclosure proposes a method in which a sensor measures andstores human activity using a GATT-based operation structure of theBluetooth LE and a client retrieves the stored information from thesensor.

FIG. 6 is a flowchart illustrating a method for forming a connectionusing Bluetooth LE between devices.

As illustrated in FIG. 6, in order to establish a Bluetooth LEconnection between a first device 300 and a second device 400, the firstdevice 300 transmits an advertisement message to the second device(S6010).

As described above, the advertisement message is used for the firstdevice 300 to provide information thereof to the other device usingBluetooth LE, and may include various information such as serviceinformation, user information, and the like provided by the device.

After checking the information included in the advertisement messagetransmitted from the first device 300, the second device 400 transmits aconnection request message for requesting Bluetooth LE connection to thefirst device 300 (S6020), and the first device 300 and the second device400 form a BLE connection (S6030).

The Bluetooth standard technology (e.g., Bluetooth Specification V4.0)is divided basic rate/enhanced data rate (BR/EDR) and low energy (LE) incore specification. Here, BR/EDR occupies the market dominant advantageof short-range wireless personal area network (WPAN) technology and is awireless communication technology applied to many products.

Bluetooth Low Energy (BLE) is a technology introduced after theBluetooth standard V4.0, which is designed to achieve higher energyefficiency than the existing Bluetooth BR/EDR.

The BLE performs communication using an industry-science-medical (ISM)frequency band (e.g., 2.4-2.4835 GHz) in the 2.4 GHz band. As describedabove, three advertising channels are used in BLE for device discovery.Here, two channels among the three designated primary advertisingchannels are present at a band edge. This will be described withreference to the following drawings. In the present disclosure, thethree primary advertising channels are collectively referred to as aprimary advertising channel set. The three advertising channels includedin the primary advertising channel set may be previously set in a deviceusing a Bluetooth protocol, and in the present disclosure, it is assumedthat channel indexes are 37, 38, and 39, but the present disclosure isnot limited thereto and the channel may have different channel indexvalues.

FIG. 7 is a diagram illustrating a frequency band of a BLE advertisingchannel, as an embodiment to which the present disclosure may beapplied.

Referring to FIG. 7, a total of 40 channels from CH0 to CH39 may be usedin an operating frequency band of BLE, and a frequency band may beallocated to each channel.

As described above, in the BLE technology, a 2.4 GHz ISM band is used asan operating frequency, and specifically, a frequency band of 2400 to2483.5 MHz may be used.

In this case, a frequency band may be allocated to each channel so thata k-th channel (here, k=0, . . . , 39) has a center frequency of2402+k*2 MHz.

The primary advertising channel set 7010 may include CH37, CH38, andCH39 as illustrated in FIG. 7. The primary advertising channel set 7010may be configured as a channel used only for advertising purposes.

Meanwhile, the data channel set 7020 represents the remaining datachannels except the three advertising channels included in the primaryadvertising channel set 7010 among the entire channels, and the datachannels represent channels used for transmitting and receiving data.

In the present disclosure, the data channel set 7020 may be referred toas an auxiliary advertising channel set. That is, in an embodiment to bedescribed later, the remaining data channels except for the threeadvertising channels included in the primary advertising channel set7010, that is, one or more data channels in the data channel set 7020,may be used as auxiliary advertising channels.

Here, CH37 and CH39 among the advertising channels of the primaryadvertising channel set 7010 are located at the edge of the BLEfrequency band including 40 channels. Since some channels of the primaryadvertising channel set 7010 used only for advertisement or scanning arelocated at both edges of the entire frequency band, there may be aproblem that efficiency of advertisement and device search due tointerference may be degraded. This will be described with reference tothe following drawings.

FIG. 8 is a diagram illustrating a frequency band of an advertisingchannel, as an embodiment to which the present disclosure may beapplied.

Referring to FIG. 8, interference may occur by other communicationtechnologies at an edge of the BLE frequency band using the 2.4 GHz ISMband. Specifically, in the vicinity of the edge including CH37, there isan auction plan of the band 2350-2390 MHz by Ofcom (British Broadcastingand Communications Commission) for LTE service.

In addition, near the edge including Ch39, a terrestrial low-powerservice band (2473-2495 MHz) has been proposed by Globalstar (USsatellite telephone service provider) following the currently providedmobile satellite service band (2483.5-2495 MHz).

As described above, since interference may occur at the edge of the BLEfrequency band by another communication technology, advertisementefficiency may be degraded when channels having channel indexes 37 and39 located at the edges of the BLE frequency band in the primaryadvertising channel set 8010 are used.

Recently, in order to solve the problem, a method of additionally usingan advertising channel other than the three existing advertisingchannels in addition to the primary advertising channel set 8010 isunder discussion.

However, in the current BLE technology, advertisements using channelsother than the primary advertising channel set (i.e., channels havingchannel indexes of 37, 38, and 39) are not possible. Therefore, in orderto perform advertisement using four or more channels, a new link layerprotocol and a new host controller interface (HCI) are required.

If it is necessary to modify the advertising channel set according tothe presence of interference, it is necessary to share the correspondinginformation between the advertiser and the scanner, but the technologydescribed above cannot be implemented if an advertising PDU defined inthe existing BLE technology is used.

Accordingly, the present disclosure proposes a link layer protocol and ahost controller interface to solve such a problem and to avoidinterference occurring at the band edge.

By additionally including another advertising channel to THE primaryadvertising channel set used in the existing BLE technology, adegradation of advertisement/scanning efficiency may be preventeddespite the presence of interference occurring at the edge of a BLEfrequency band and reliability of discovery of a BLE device may beincreased.

FIG. 9 is a diagram illustrating an advertising channel set thatadditionally uses an advertising channel, as an embodiment to which thepresent disclosure is applied.

In the related art BLE technology, an advertising event may be definedas shown in (a) of FIG. 9. An advertising event represents a series ofone or more advertising packets transmitted from an advertiser throughan advertising channel. The advertising packet may include anadvertising channel PDU.

That is, as in the related art BLE technology, in the case of usingthree advertising channels, advertising packets may be transmitted inthree advertising channels during an advertising event, and a timeinterval of 10 ms or less (i.e., advertising time) may be allocated foreach advertising packet transmission.

In an embodiment of the present disclosure, when four advertisingchannels are used, an advertising event may be defined as shown in (b)of FIG. 9. The channel index added to the existing advertising channelset is defined as having a value of n. During the advertising event, anadvertising packet may be transmitted in four advertising channels, andthe same time interval of 10 ms or less as that of the existing case maybe allocated to each advertising packet transmission.

In this case, a new generic access profile (GAP) timer may be set. Thiswill be described with reference to the following drawings.

FIG. 10 is a diagram illustrating a generic access profile (GAP) timeraccording to the use of an additional advertising channel, as anembodiment to which the present disclosure is applied.

In an embodiment of the present disclosure, an advertising event andinterval may be defined as shown in (a) of FIG. 10. As described above,the advertising event may include one or more advertisement times fortransmitting an advertising packet.

In addition, a time allocated for the advertising event (i.e.,T_advEvent) may include an advertisement interval (i.e., advInterval) inwhich an advertising packet is actually transmitted and an advertisementdelay (i.e., advDelay) indicating a delay time that may occur in theprocess of transmitting the advertising packet).

In order to apply the method proposed in the present disclosure, a timervalue for an advertisement or scanning of a GAP may be changed as shownin (b) of FIG. 10.

In detail, a minimum value of T_GAP (adv_fast_interval1_coded)indicating an advertisement interval from minimum to maximum in a GAPmode of the LE coded PHY may be changed to 120 ms. In the GAP mode ofthe LE 1M PHY, a minimum value of T_GAP (adv_fast_interval1) indicatingan advertisement interval from minimum to maximum may be changed to 40ms.

In addition, T_GAP (scan_fast_interval) indicating a scan interval of adiscovery or connection establishment procedure in the LE 1M PHY mayhave a value of 40 ms to 80 ms. T_GAP (scan_fast_window_coded)indicating a scan window of the discovery or connection establishmentprocedure in the LE coded PHY may be changed to 80 ms. T_GAP(scan_fast_window) indicating a scan window of the discovery orconnection establishment procedure in the LE 1M PHY may be changed to 80ms.

In other words, as the advertising channels included in the advertisingchannel set increases from three channels to four channels, timer valuesdefined in the GAP may be changed as shown in FIG. 10.

FIG. 11 is a diagram illustrating an advertising channel setadditionally using an advertising channel, as an embodiment to which thepresent disclosure is applied.

Referring to FIG. 11, unlike the method described with reference to FIG.9, advertising packets may be transmitted in four advertising channelswithin the same length as the advertising event length (or interval) inthe existing BLE technology.

Therefore, since four advertisement times are allocated at a fixedlength, each advertisement time may be reduced as shown in FIG. 11.Specifically, an interval of 7.5 ms or less may be allocated to eachadvertisement time.

Hereinafter, a method of configuring an advertising channel set byreplacing a channel having interference with another channel, whilemaintaining the number of advertising channels to be equal to 3 which isthe same as the existing case will be described.

FIG. 12 shows an example of an advertising event according to a modifiedadvertising channel set, as an embodiment to which the presentdisclosure is applied.

Referring to FIG. 12, an existing advertising channel set and a modified(or updated) advertising channel set may equally include threeadvertising channels. Hereinafter, for convenience of descriptionherein, the existing advertising channel set may be designated as afirst advertising channel set (or a primary advertising channel set),and the modified (or updated) advertising channel set may be designatedas a second advertising channel set (or an auxiliary advertising channelset).

The first advertising channel set may include three advertising channels(i.e., channels having channel indexes of 37, 38, and 39) (refer to thedescription in (a) of FIG. 9 above). When interference exists in any oneof the advertising channels included in the first advertising channel,the channel in which the interference exists may be replaced (ormodified) with another channel. The replacing channel may be any onechannel of the data channel set, and a channel index may have a certainvalue (hereinafter, denoted as n) among index values of the remainingchannels except for the advertising channels included in the firstadvertising channel set.

Referring to FIG. 12(a), it is assumed that interference exists (oroccurs) in CH39. In this case, the second advertising channel set may begenerated by replacing CH39 of the first advertising channel set withCHn.

Referring to FIG. 12(b), it is assumed that interference exists in CH37.In this case, the second advertising channel set may be generated byreplacing CH37 of the first advertising channel set with CHn.

Referring to FIG. 12(c), it is assumed that interference exists in CH38.In this case, the second advertising channel set may be generated byreplacing CH38 of the first advertising channel set with CHn.

Advertisement may be performed using the second advertising channel setmodified (or updated) from the first advertising channel set. In thiscase, the advertisement may be performed, while maintaining the samelength, advertisement time, or interval of the existing advertisingevent.

FIG. 13 shows an example of a method of performing an advertisementusing four fixed channels, as an embodiment to which the presentdisclosure is applied.

Referring to FIG. 13, it is assumed that an existing advertising channelset includes four advertising channels instead of three advertisingchannels. In this embodiment, advertising packets may be transmitted andreceived between BLE devices using the four fixed channels.

In other words, in this embodiment, a new physical channel set (i.e., aprimary advertising channel set) including four advertising channels maybe defined. Channel indexes of the four advertising channels may havevalues of 37, 38, 39 and n, respectively.

In addition, a channel set including channels other than channelsincluded in the newly defined physical channel set may configure a datachannel set (or a reporting advertising channel set).

FIG. 13(a) shows an advertising channel map of an existing primaryadvertising channel set including three advertising channels. When fourfixed advertising channels are used as a primary advertising channelset, a field indicating an added channel may be added to the advertisingchannel map as shown in FIG. 13(b).

An advertising channel map parameter illustrated in FIG. 13 may beincluded in an LE_Set_Advertising_Parameters Command among the HCIcommands.

Also, the advertiser may perform advertisement using the new physicalchannel set. In this case, the method described above with reference toFIGS. 9 through 11 may be applied to a link layer operation in the samemanner. The scanner may perform scanning during a scan window on the newphysical channel set.

As described above, a primary advertising channel set may be configuredusing four advertising channels, and advertisement or scanning may beperformed using the corresponding primary advertising channels.Hereinafter, a method of using a primary advertising channel includingthree advertising channels and applying a protected mode of anadvertising channel according to the presence of interference, whileusing primary advertising channels including three advertising channelswill be described.

In an embodiment of the present disclosure, a protected mode may beapplied when interference exists, and a non-protected mode may beapplied when interference does not exist. The BLE device may recognizewhether there is interference in the existing advertising channel set invarious ways. For example, the device may recognize whether theinterference exists by using a higher level, an application, or thelike, and may receive related information from the user.

If there is no interference, that is, in the non-protected mode, theadvertiser may perform advertisement in the same manner as the existingcase. If there is interference, that is, in the protected mode, theadvertiser may perform advertisement on four advertising channels (newadvertising channel is added) or three advertising channels (channelhaving interference is replaced).

In addition, when the protected mode is applied by determining whetherthe protected mode is to be applied by the advertiser, the scanner mayperform scanning using four channels. A new advertising channel PDU maybe used when the scanner determines whether to apply the protected modefrom the advertiser. Details thereof will be described later.

In the case of using four advertising channels in the protected mode,the scanner is not required to know which channel has interference, andadvertisement/scanning may be performed advantageously using the fourpredetermined channels. Meanwhile, advertisement efficiency may belowered due to continuous use of the channel in which interferenceexists. In this case, the advertiser and the scanner need to sharewhether to use the protected mode.

When three advertising channels are used in the protected mode, sinceadvertisement/scanning is not performed on the channel in whichinterference exists, a discovery time or discovery efficiency mayincrease. Meanwhile, the advertiser and scanner need to share whichchannel is to be discarded or which channel has interference. Even inthis case, the advertiser and the scanner need to share whether theprotected mode is to be used or not.

FIG. 14 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

Referring to FIG. 14, whether to apply the protected mode may beindicated by the advertiser, i.e., the second device 400.

In case where interference is detected, a host of the second device 400transmits an LE Set Advertising Protection Enable command to a linklayer (LL) of the second device 400 in order to apply the protected mode(S14010). The LE Set Advertising Protection Enable command may have asize of one octet, and if the value is 0x00, it may indicatedeactivation of the protected mode, that is, the non-protected mode, andif the value is 0x01, it may indicate activation of the protected mode.

The LL of the second device 400 may transmit a command completionmessage indicating that the command is successfully completed to thehost of the second device 400 (S14020).

The LL of the second device 400 transmits an ADV CH UPDATE INDindicating the updating (or modification) of the advertising channels toan LL of the first device 300 (S14030). In this case, the LL of thesecond device 400 may transmit the ADV CH UPDATE IND a plurality oftimes during a preset advertising channel update interval.

The LL of the first device 300 transmits a message indicating that theADV CH UPDATE IND PDU has been received to the host of the first device300 (S14040). This may trigger the protected mode.

The host of the first device 300 indicates activation (or application)of the protected mode and transmits an LE Set Advertising ProtectionEnable command to the LL of the first device 300 (S14050). The LL of thefirst device 300 may transmit a command completion message indicatingthat the command has been successfully completed to the host of thefirst device 300 (S14060).

Thereafter, the second device 400 may perform advertisement by using theupdated advertising channel set, and the first device 300 may performscanning by using the updated advertising channel set.

FIG. 15 is a diagram illustrating a format of an advertising packetindicating whether to apply a protected mode of an advertising channel,as an embodiment to which the present disclosure is applied.

The LL of the second device 400 may use an advertising channel PDU asshown in FIG. 15 to inform the LL of the first device 300 as to whetherto use the protected mode. As described above, the advertising channelPDU may be transmitted a plurality of times, and in this case, theadvertising channel PDU may be transmitted for a predetermined interval.

The advertising channel PDU indicating whether to use the protected modemay include a payload having the format of FIG. 15(a). Specifically, thepayload may include an AdvA field indicating an address of theadvertiser and an AdvChSet field indicating the advertising channel set.

In addition, the AdvChSet field may have a format shown in FIG. 15(b).Specifically, when the AdvChSet field is 0x00, advertisement may beperformed using three channels included in the existing primaryadvertising channel set. If the AdvChSet field is 0x01, advertisementmay be performed using a total of four channels including an additionalchannel having a channel index of n in the three channels included inthe existing primary advertising channel set.

In the above, the method of setting the protected mode on aconnectionless basis has been described. Hereinafter, a method ofsetting a protected mode on a connection basis will be described.

FIG. 16 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

The first device 300 forms a BLE connection with the second device 400.In this case, the method described above with reference to FIG. 6 may beapplied.

When interference is detected, the host of the first device 300transmits an LE Set Advertising Protection Enable command to the LL ofthe first device 300 in order to apply the protected mode (S16010). TheLE Set Advertising Protection Enable command may have a size of 1 octet,and when the LE Set Advertising Protection Enable command value is 0x00,it may indicate deactivation of the protected mode, that is, thenon-protected mode (or a default mode), and when the LE Set AdvertisingProtection Enable command value is 0x01, it may indicate activation ofthe protected mode.

The LL of the first device 300 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the first device 300 (S16020).

The LL of the first device 300 transmits an ADV CH UPDATE IND indicatingupdating (or modification) of the advertising channels to the LL of thesecond device 400 (S16030). In this case, the LL of the first device 300may transmit the ADV CH UPDATE IND a plurality of times for a presetadvertising channel update interval.

The LL of the second device 400 transmits a message indicating that theADV CH UPDATE IND PDU has been received to the host of the second device400 (S16040). This may trigger the protected mode.

The host of the second device 400 indicates activation (or application)of the protected mode and transmits an LE Set Advertising ProtectionEnable command to the LL of the second device 400 (S16050). The LL ofthe second device 400 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the second device 400 (S16060).

Thereafter, the second device 400 may perform advertisement using theupdated advertising channel set, and the first device 300 may performscanning using the updated advertising channel set.

FIG. 17 is a diagram illustrating an example of a format of a controlmessage indicating whether to apply a protected mode of an advertisingchannel, as an embodiment to which the present disclosure is applied.

The first device 300 may use a link layer control PDU as shown in FIG.17 to indicate whether to use the protected mode to the second device400. As described above, the control PDU may be transmitted a pluralityof times, in which case the control PDU may be transmitted for apredetermined interval.

The link layer control PDU indicating whether to use the protected modemay include a payload having the format of FIG. 17(a). Specifically, thepayload may include an Opcode field indicating an operation code and aCtrData field indicating control data.

In addition, the CtrData field may have a format shown in FIG. 17(b).Specifically, when the CtrData field is 0x00, advertisement may beperformed using the three channels included in the existing primaryadvertising channel set. If the CtrData field is 0x01, advertisement maybe performed using a total of four channels including the additionalchannel n in the three channels included in the existing primaryadvertising channel set.

Meanwhile, prior to transmitting a control message indicating theapplication of the protected mode, information about an availableadvertising channel set or advertising channels may be exchanged byperforming a negotiation procedure between the first device 300 and thesecond device 400. This will be described with reference to thefollowing drawings.

FIG. 18 is a flowchart illustrating a method of modifying an advertisingchannel set through a negotiation procedure according to whetherinterference exists in an advertising channel, as an embodiment to whichthe present disclosure is applied.

The first device 300 forms a BLE connection with the second device 400.In this case, the method described above with reference to FIG. 6 may beapplied.

When interference is detected, the host of the first device 300transmits an LE SetAdvertising Protection Enable command to the LL ofthe first device 300 in order to apply the protected mode (S18010). TheLE Set Advertising Protection Enable command may have a size of 1 octet,and when the LE Set Advertising Protection Enable command value is 0x00,it may indicate deactivation of the protected mode, that is, thenon-protected mode (or default mode), and when the LE SetAdvertisingProtection Enable command value is 0x01, it may indicate activation ofthe protected mode.

The LL of the first device 300 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the first device 300 (S18020).

The LL of the first device 300 transmits an advertising channel requestmessage for requesting information related to an available advertisingchannel set (or available auxiliary advertising channels) to the LL ofthe second device (S18030). The LL of the second device transmits anadvertising channel response message including information related to anavailable advertising channel set or an available auxiliary advertisingchannel in the second device (S18040). Here, the auxiliary advertisingchannel indicates an advertising channel added to the primaryadvertising channel set.

ADV CH UPDATE IND indicating updating (or modification) of theadvertising channel is transmitted to the LL of the second device 400(S18050). In this case, the ADV CH UPDATE IND may be a control messagedetermined based on the information received in operation S18040.

The LL of the second device 400 transmits a message indicating that theADV CH UPDATE IND PDU has been received to the host of the second device400 (S18060). This may trigger the protected mode.

The host of the second device 400 indicates activation (or application)of the protected mode and transmits an LE Set Advertising ProtectionEnable command to the LL of the second device 400 (S18070). The LL ofthe second device 400 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the second device 400 (S18080).

Thereafter, the second device 400 may perform advertisement using theupdated advertising channel set, and the first device 300 may performscanning using the updated advertising channel set.

FIG. 19 is a diagram illustrating a format of a control messageindicating whether to apply a protected mode of an advertising channel,as an embodiment to which the present disclosure is applied.

The first device 300 may use a link layer control PDU as shown in FIG.19 to indicate to the second device 400 as to whether to use theprotected mode.

The link layer control PDU indicating whether to use the protected modemay include a payload having the format of FIG. 19(a). Specifically, thepayload may include an Opcode field indicating an operation code and aCtrData field indicating control data.

In this case, the CtrData field may have a format shown in FIG. 19(b).Specifically, when the CtrData field is 0, advertisement may beperformed using the three channels included in the existing primaryadvertising channel set. If the CtrData field is 1, advertisement may beperformed using a second advertising channel set including an auxiliaryadvertising channel having a channel index n in addition to the threechannels included in the existing primary advertising channel set. Ifthe CtrData field is 2, advertisement may be performed using a secondadvertising channel set in which a channel in which interference existsamong the three channels included in the existing primary advertisingchannel set is replaced with the auxiliary advertising channel havingthe channel index n.

As described above, the value of the CtrData field may be determinedbased on the available advertising channel set or available auxiliaryadvertising channel information exchanged in the negotiation procedurewith the second device 400 (S18030 and S18040 in FIG. 18 above).

In addition, the format illustrated in FIG. 19(b) may be a format ofcontrol data included in a response message transmitted from the seconddevice 400 in the negotiation procedure.

Hereinafter, an embodiment of applying an advertising channel protectionmethod based on three channels will be described. In the presentembodiment, in the non-protected mode where there is no interference,advertisement/scanning may be performed in the existing primaryadvertising channel set. In the case of the protected mode in whichinterference exists, advertisement/scanning may be performed by using anauxiliary advertising channel set including three advertising channelsby adding a new auxiliary advertising channel instead of the advertisingchannel including a strong interference signal.

FIG. 20 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether interference exists in an advertisingchannel, as an embodiment to which the present disclosure is applied.

If interference is detected, the host of the second device 400 transmitsan LE Set Advertising Protection command to the LL of the second device400 in order to apply the protected mode (S20010). The LE SetAdvertising Protection command may have a size of 1 octet. When the LESet Advertising Protection command has a value of 0x00 it may indicatedeactivation of the protected mode, that is, the non-protected mode, andwhen the LE Set Advertising Protection command has a value of 0x01, itmay indicate activation of the protected mode. In addition, the LE SetAdvertising Protection command may include discarded channel (i.e.,channel with strong interference) information and/or added channel(i.e., auxiliary advertising channel) information.

Subsequent steps S20020, S20030, S20040, S20050, and S20060 may beperformed in the same manner as steps S14020, S14030, S14040, S14050,and S14060 of FIG. 14 described above.

Thereafter, the second device 400 may perform advertisement using theupdated advertising channel set, and the first device 300 may performscanning using the updated advertising channel set.

FIG. 21 is a diagram illustrating an example of a format of anadvertising packet indicating whether to apply a protected mode of anadvertising channel, as an embodiment to which the present disclosure isapplied.

The LL of the second device 400 may use an advertising channel PDU asshown in FIG. 21 to inform the LL of the first device 300 as to whetherto use the protected mode. As described above, the advertising channelPDU may be transmitted a plurality of times, and in this case, it may betransmitted for a predetermined interval.

The advertising channel PDU indicating whether to use the protected modemay include a payload having the format of FIG. 21(a). Specifically, thepayload may include an AdvA field indicating an address of anadvertiser, a DropAdvCh field indicating a dropped advertising channel,and an AddAdvCh field indicating an added advertising channel.

The DropAdvCh field may have a format shown in FIG. 21(b). Specifically,a value of the DropAdvCh field may indicate an index of a replacedadvertising channel. The AddAdvCh field may have a format shown in FIG.21(c). Specifically, a value of the AddAdvCh field may indicate an indexof an added advertising channel.

In the above, the method of setting the protected mode on aconnectionless basis. Hereinafter, a method of setting a protected modeon a connection basis will be described.

FIG. 22 is a flowchart illustrating a method of modifying an advertisingchannel set according to whether an interference exists in anadvertising channel, as an embodiment to which the present disclosure isapplied.

The first device 300 forms a BLE connection with the second device 400.In this case, the method described above with reference to FIG. 6 may beapplied.

When interference is detected, the host of the first device 300transmits an LE SetAdvertising Protection Enable command to the LL ofthe first device 300 in order to apply the protected mode (S22010). TheLE Set Advertising Protection Enable command may have a size of 1 octet,and when a value of the LE Set Advertising Protection Enable commandvalue is 0x00, it may indicate deactivation of the protected mode, thatis, the non-protected mode (or default mode), and when the value of theLE Set Advertising Protection Enable command value is 0x01, it mayindicate activation of the protected mode.

The LL of the first device 300 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the first device 300 (S22020).

The LL of the first device 300 transmits an ADV CH UPDATE IND indicatingupdating (or modification) of the advertising channel to the LL of thesecond device 400 (S22030).

The LL of the second device 400 transmits a message indicating that theADV CH UPDATE IND PDU has been received to the host of the second device400 (S22040). This may trigger the protected mode.

The host of the second device 400 indicates activation (or application)of the protected mode and transmits an LE Set Advertising ProtectionEnable command to the LL of the second device 400 (S22050). The LL ofthe second device 400 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the second device 400 (S22060).

Thereafter, the second device 400 may perform advertisement by using theupdated advertising channel set, and the first device 300 may performscanning by using the updated advertising channel set.

In this case, the link layer control message transmitted in step S22030may include the payload of FIG. 21(a). The dropped channel informationor the added channel information included in the payload will bedescribed with reference to the following drawings.

FIG. 23 is a diagram illustrating an example of a format of controlinformation including advertising channel information related toapplication of a protected mode of an advertising channel, as anembodiment to which the present disclosure is applied.

The information related to the advertising channel included in the linklayer control PDU indicating updating (or modification) of theadvertising channel may have a format as shown in FIG. 23.

In other words, the link layer control PDU indicating updating of theadvertising channel may include index information of a channel droppedand index information of a channel added due to the presence ofinterference.

Subsequently, the first device 300 and the second device 400 may performadvertisement/scanning by using the updated second advertising channelset including the auxiliary advertising channel instead of the channelin which the interference exists.

Meanwhile, prior to transmitting the control message indicating theapplication of the protected mode, information on the availableadvertising channel set or advertising channels may be exchanged byperforming a negotiation procedure between the first device 300 and thesecond device 400.

FIG. 24 is a flowchart illustrating a method of modifying an advertisingchannel set through a negotiation procedure according to whetherinterference exists in an advertising channel, as an embodiment to whichthe present disclosure is applied.

The first device 300 forms a BLE connection with the second device 400.In this case, the method described above with reference to FIG. 6 may beapplied.

When interference is detected, the host of the first device 300transmits an LE SetAdvertising Protection Enable command to the LL ofthe first device 300 in order to apply the protected mode (S24010). TheLE Set Advertising Protection Enable command may have a size of 1 octet,and when the LE Set Advertising Protection Enable command value is 0x00,it may indicate deactivation of the protected mode, that is, thenon-protected mode (or the default mode), and when the LE SetAdvertising Protection Enable command value is 0x01, it may indicateactivation of the protected mode.

The LL of the first device 300 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the first device 300 (S24020).

The LL of the first device 300 transmits an advertising channel requestmessage for requesting information related to an available advertisingchannel set (or available auxiliary advertising channel) to the LL ofthe second device (S24030). The LL of the second device transmits anadvertising channel response message including information related tothe available advertising channel set or available auxiliary advertisingchannel in the second device (S24040). Here, the auxiliary advertisingchannel indicates an advertising channel added to the primaryadvertising channel set.

ADV CH UPDATE IND indicating updating (or modification) of theadvertising channel is transmitted to the LL of the second device 400(S24050). Here, the ADV CH UPDATE IND may be a control messagedetermined based on the information received in step S24040.

The LL of the second device 400 transmits a message indicating that theADV CH UPDATE IND PDU has been received to the host of the second device400 (S24060). This may trigger the protected mode.

The host of the second device 400 indicates activation (or application)of the protected mode and transmits an LE Set Advertising ProtectionEnable command to the LL of the second device 400 (S24070). The LL ofthe second device 400 may transmit a command completion messageindicating that the command has been successfully completed to the hostof the second device 400 (S24080).

Thereafter, the second device 400 may perform advertisement using theupdated advertising channel set, and the first device 300 may performscanning using the updated advertising channel set. The first device 300and the second device 400 may perform advertisement/scanning by usingthe updated second advertising channel set including the auxiliaryadvertising channel instead of the channel having interference.

FIG. 25 is a diagram illustrating a method of protecting an advertisingchannel in a mesh network, as an embodiment to which the presentdisclosure is applied.

Referring to FIG. 25, a plurality of BLE devices may configure a meshnetwork. The BLE devices constituting the mesh network transmit andreceive a mesh packet through an advertising bearer.

In the case of using the protected mode for protecting an advertisingchannel in such a mesh network, the number of channels that the BLEdevice needs to scan increases, which may cause a problem that aprobability of receiving a mesh packet quickly is lowered.

Therefore, the present disclosure proposes a method in which a nodewhich grasps (or recognizes) an interference state of a BLE advertisingchannel among nodes constituting a mesh network shares it with theentire mesh network to perform advertising channel protection without aseparate HCI command. The node which grasps the interference state ofthe BLE advertising channel may inform the mesh network to operate inthe non-protected mode when interference is low and to operate in theprotected mode when interference is high.

FIG. 26 is a diagram illustrating an example of a method of releasingprotection of an advertising channel in a mesh network, as an embodimentto which the present disclosure is applied.

Referring to FIG. 26, it is assumed that the BLE devices S1 to S9 form amesh network and a protected mode is set.

The S3 device constituting one node of the mesh network performs aprocedure of checking, with the external device, a degree ofinterference existing in an advertising channel set (S26010).

As a result of checking in step S26010, if there is no interference inthe existing advertising channel set or if the interference is smallerthan a predetermined value, the S3 device sends an ADV CH UPDATE INDindicating modification of the advertising channel set to the otherdevices of the mesh network (S26020).

In this case, the S3 device may transmit the ADV CH UPDATE IND aplurality of times during preset advertising channel update interval.This may cause the protected mode to be released and the mesh network tobe switched to a non-protected mode. In the non-protected mode,advertisement/scanning may be performed using the existing primaryadvertising channel set.

FIGS. 27 and 28 illustrate a method of applying a protected mode of anadvertising channel according to an interference environment for eachregion in the case of establishing a wide area mesh network, as anembodiment to which the present disclosure is applied.

Referring to FIG. 27, when a wide area mesh network is established, aninterference environment experienced by a mesh node may vary dependingon an area. In this case, the protected mode needs to be applieddifferently according to the area.

For example, if interference exists in an advertising channel only inone of a first area 27010 and a second area 27020 included in the widearea mesh network, the protected mode may be applied only to the areawhere interference exists, thereby effectively protecting theadvertising channel in the mesh network.

In an embodiment of the present disclosure, by limiting the number ofhops available for transmission of a PDU indicating whether a protectedmode is applied from a triggering node, the same mode may be appliedonly to nodes in areas having a similar interference environment. Here,the triggering node indicates a node that initially transmits anindication message indicating modification of the protected mode.

In other words, the triggering node that checks the interference stateand starts modification of the protected mode may transmit an ADV CHUPDATE IND indicating updating of the advertising channel. The ADV CHUPDATE_IND may be a link layer advertising channel PDU defined in a meshnetwork.

In this case, the ADV CH UPDATE IND message may include a payload asshown in FIG. 28.

In particular, in the case of applying a method using the 4channel-based advertising channel set, a field indicating a maximum hopcount may be added to the payload as shown in FIG. 28(a).

In addition, in the case of applying a method of using a 3 channel-basedadvertising channel set, a field indicating a maximum hop count may beadded to the payload as shown in FIG. 28(b).

After receiving the corresponding PDU at each node, relay may beperformed by reducing the hop count field of the payload by 1.

FIGS. 29 and 30 are flowcharts illustrating a method of modifying ascanning mode according to the presence or absence of interference, asan embodiment to which the present disclosure may be applied.

In an embodiment of the present disclosure, the scanner may activate theprotected mode if there is interference and deactivate the protectedmode if there is no interference, regardless of state of the advertiser.If the advertiser device is a new device, it may use four channels, andif the advertiser device is a legacy device, it may use three channels.

Referring to FIG. 29, a method in which the first device 300 releases aprotected mode according to a state of interference on the assumptionthat the protected mode is previously activated. Also, it is assumedthat advertisement/scanning is performed using a total of fouradvertising channels including an auxiliary advertising channel in theprimary advertising channel set in the protected mode.

The host of the first device 300 recognizes that there is nointerference in the primary advertising channel set, and sends an LE SetAdvertising Protection command to the LL of the first device 300 toindicate deactivation of the protected mode. (S29010). The LL of thefirst device 300 transmits a completion message including informationrelated to the result of the command to the host of the first device 300(S29020). The LE Set Advertising Protection command, which is an HCIcommand, may have the format shown in FIG. 30.

Specifically, the LE Set Advertising Protection command may include acommand parameter. The command parameter indicates a parameterinstructing setting or release the advertisement protected mode. The LESet Advertising Protection command may include a return parameter. Thereturn parameter may indicate a command processing result state or acurrent advertisement protected mode state.

When the command parameter indicates the use of the protected mode, theLL of the first device 300 may perform four channel scanning. When thecommand parameter indicates that the protected mode is not used, the LLof the first device 300 may perform three-channel scanning.

That is, the LL of the second device 400 performs advertisement, and theLL of the first device 300 performs scanning on three channels (i.e., aprimary advertising channel) (S29030). After scanning the advertisementmessage, the LL of the first device 300 transmits a scan request messagerequesting supplemental information (S29040). The LL of the seconddevice 400 transmits a scan response message including supplementalinformation in response to the scan request message (S29050).

The LL of the first device 300 transmits an LE advertisement reportmessage including information related to the advertisement result to thehost of the first device 300 (S29060).

FIG. 31 is a diagram illustrating an operation between a new device anda legacy device when a protected mode of an advertising channel isapplied, as an embodiment to which the present disclosure may beapplied.

Referring to FIG. 31(a), it is assumed that an advertiser device is anew device and a scanner device is a legacy device. In this case, whenthe four-channel-based dynamic advertising method described above withreference to FIGS. 14 to 19 is applied, the advertiser may increase thenumber of advertising channel sets to four after the occurrence ofinterference to perform advertisement.

Meanwhile, since the scanner scans only the channels having channelindexes 37, 38, and 39, which are the primary advertising channels, wheninterference exists at a BLE band edge (e.g., channel 37), the scannermay perform scanning using an existing advertising channel including aninterfered channel.

Referring to FIG. 31(b), it is assumed that the advertiser device is alegacy device and a scanner device. Here, the advertiser instructswhether to apply the protected mode for each extended advertising event.In contrast, the scanner may perform a four-channel-based fixed scanningoperation.

FIG. 32 is a diagram illustrating a method of applying a protected modeof an advertising channel, as an embodiment to which the presentdisclosure may be applied.

Referring to FIG. 32(a), a master device may use the protected mode in aBLE connection state with a slave device. Specifically, after the masterdevice is connected to the slave device at an initial state, the masterdevice may transmit a protected mode activation message for applying thedynamic advertising described above with reference to FIGS. 14 to 24 inthe connected state.

The slave device transmits an available (or preferred) advertisingchannel set (or available advertising channel) to the master device, andthen updates the advertising channel set based on information receivedfrom the master device.

Referring to FIG. 32(b), after the BLE connection is released, themaster device and the slave device may perform advertisement andscanning using the updated advertising channel set in the protectedmode. This effectively reduces a discovery time of a peer device afterthe advertising channel is updated.

FIG. 33 is a diagram illustrating a method of periodically indicatingwhether a protected mode of an advertising channel is applied, as anembodiment to which the present disclosure may be applied.

Referring to FIG. 33, the advertiser may periodically inform about theprotected mode at each extended advertising event. The advertiser maytransmit a packet indicating whether to apply the protected mode in theprimary advertising channel when initiating the extended advertisingevent. Thereafter, an indication message related to an extendedadvertising event in the updated advertising channel set, that is, thereporting advertising channel set, may be transmitted according towhether the protected mode is applied.

The scanner may perform scanning after maintaining or changing theprotected mode through the advertising channel PDU indicating updatingof the received advertising channel.

FIG. 34 is a diagram illustrating a method for periodically indicatingwhether to apply a protected mode of an advertising channel, as anembodiment to which the present disclosure may be applied.

Referring to FIG. 34, an Angle of Arrival (AoA)/AriD of Departure (AoD)may be performed by transmitting supplemental information for directfinding through extended advertisement.

If reception efficiency of the above-described ADV EXT IND PDU isdecreased due to interference present in the 2.4 GHz BLE band,efficiency of indoor positioning or asset tracking may be reduced.However, in the case of applying the advertising channel protectionmethod proposed in the present disclosure, it is possible to improvetransmission efficiency of advertisement and transmission efficiency ofsupplemental information of the extended advertising event through theupdated advertising channel set.

FIG. 35 is a diagram illustrating a method of applying a protected modeof an advertising channel according to an interference environment foreach region in the case of establishing a wide area mesh network, as anembodiment to which the present disclosure may be applied.

Referring to FIG. 35, when a wide area mesh network is established, aninterference environment experienced by a mesh node may vary accordingto an area. In this case, the protected mode needs to be applieddifferently according to the area.

For example, if interference exists in an advertising channel only inone of a first area 35010 and a second area 35020 included in the widearea mesh network, the protected mode may be applied only to an areawhere interference exists, thereby effectively protecting theadvertising channel in the mesh network.

As described above with reference to FIG. 27, it is possible to managethe advertising channel set for each area based on a hop count. In thiscase, a message indicating updating of different advertising channelsets may be transmitted to a node existing at the edge of each area.

For example, when a node S5 existing at an area edge of the first area3510 and the second area 3520 receives different ADV CH UPDATE IND PDUs,the node S5 may transfer a packet to a next hole using a legacyadvertising channel set without modifying the protected mode.

FIG. 36 illustrates an example of a method for protecting an advertisingchannel, as an embodiment to which the present disclosure is applied.

Referring to FIG. 36, the first device recognizes an advertising channelin which interference exists among three advertising channelsconstituting a first advertising channel set (S36010).

When the first device recognizes an advertising channel in whichinterference exists in step S3601, the first device transmits a commandmessage indicating application of the protected mode to the seconddevice (S36020).

Here, the protected mode indicates a mode for transmitting and receivinga message using a second advertising channel set updated from the firstadvertising channel set in a non-connection state.

The first device receives an advertisement message from the seconddevice through the second advertising channel set (S36030).

As described above, the second advertising channel set may be updated toadditionally include at least one advertising channel in addition to thethree advertising channels constituting the first advertising channelset.

In this case, the control message may include at least one of operationcode information indicating updating of the first advertising channelset, index information of an additionally included advertising channel,or information on the number of advertising channels included in thesecond advertising channel set.

In addition, as described above, the second advertising channel set maybe updated to replace the advertising channel having interference with aspecific channel among data channels used for transmitting and receivingdata.

In this case, the control message may include at least one of operationcode information indicating updating of the first advertising channelset, index information of an advertising channel in which interferenceexists, or index information of the replacing specific channel.

In addition, as described above, the first device may transmit a requestmessage for requesting information related to updating of the firstadvertising channel set to the second device. The first device mayreceive a response message including information related to the updatingin response to the request message from the second device.

In addition, the information related to the updating may includeinformation related to an auxiliary advertising channel available in thesecond device or information related to an advertising channel setavailable in the second device.

In addition, as described above, the first device and the second devicemay configure a mesh network.

In this case, the control message may include at least one of operationcode information indicating updating of the first advertising channelset, index information of an advertising channel having interference,index information of an advertising channel added to the firstadvertising channel set, the number information of the advertisingchannel included in the second advertising channel set, or hop countinformation for limiting a maximum hop number.

In addition, the control message may be dropped or transmitted to one ormore adjacent devices by the second device according to the hop countvalue.

The present invention descried above is not limited to theabove-described embodiments and the accompanying drawings because thosehaving ordinary skill in the technical field to which the presentinvention pertains can make various replacements, variations andmodifications within the range which does not depart from the technicalspirit of the invention.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a method and apparatus for discoveringan adjacent device using Bluetooth low energy (LE). In particular, themethod performed by a first device includes: recognizing an advertisingchannel in which interference exists among three advertising channelsconstituting a first advertising channel set; transmitting a controlmessage instructing application of a protected mode to a second device,when the advertising channel in which interference exists is recognized,the protected mode indicating a mode for transmitting and receiving amessage using a second advertising channel set updated from the firstadvertising channel set in a non-connection state; and receiving anadvertisement message from the second device through the secondadvertising channel set.

The invention claimed is:
 1. A method for discovering an adjacent devicein a wireless communication system using Bluetooth low energy (LE),which is performed by a first device, the method comprising: recognizingan advertising channel in which interference exists among threeadvertising channels constituting a first advertising channel set;transmitting a control message instructing application of a protectedmode to a second device, based on that the advertising channel in whichinterference exists is recognized, the protected mode indicating a modefor transmitting and receiving a message using a second advertisingchannel set updated from the first advertising channel set in anon-connection state; and receiving an advertisement message from thesecond device through the second advertising channel set, wherein thecontrol message comprises operation code information instructingupdating of the first advertising channel set.
 2. The method of claim 1,wherein the second advertising channel set is updated to additionallyinclude at least one advertising channel in addition to the threeadvertising channels constituting the first advertising channel set. 3.The method of claim 2, wherein the control message further comprises atleast one of index information of the additionally included advertisingchannel, or number information of the advertising channels included inthe second advertising channel set.
 4. The method of claim 1, whereinthe second advertising channel set is updated to replace the advertisingchannel in which interference exists with a specific channel among datachannels used for transmitting and receiving data.
 5. The method ofclaim 4, wherein the control message further comprises at least one ofindex information of the advertising channel in which interferenceexists, or index information of the replacing specific channel.
 6. Themethod of claim 1, further comprising: transmitting a request messagerequesting information related to updating of the first advertisingchannel set to the second device; and receiving a response messageincluding the information related to updating in response to the requestmessage from the second device.
 7. The method of claim 6, wherein theinformation related to updating comprises information related to anauxiliary advertising channel available in the second device orinformation related to an advertising channel set available in thesecond device.
 8. The method of claim 1, wherein the first device andthe second device form a mesh network.
 9. The method of claim 8, whereinthe control message further comprises at least one of index informationof the advertising channel in which interference exists, an indexinformation of an advertising channel added to the first advertisingchannel set, number information of the advertising channels included inthe second advertising channel set, or hop count information forlimiting a maximum hop number.
 10. The method of claim 9, wherein thecontrol message is dropped or transmitted to one or more adjacentdevices by the second device according to the hop count value.
 11. Adevice for discovering an adjacent device in a wireless communicationsystem using Bluetooth low energy (LE), the device, as a first device,comprising: a communication unit configured to communicate with anexternal device wirelessly or wiredly; and a processor functionallyconnected to the communication unit, wherein the processor recognizes anadvertising channel in which interference exists among three advertisingchannels constituting a first advertising channel set, transmits acontrol message instructing application of a protected mode to a seconddevice, based on that the advertising channel in which interferenceexists is recognized, the protected mode indicating a mode fortransmitting and receiving a message using a second advertising channelset updated from the first advertising channel set in a non-connectionstate, and receives an advertisement message from the second devicethrough the second advertising channel set, wherein the control messagecomprises operation code information instructing updating of the firstadvertising channel set.
 12. The device of claim 11, wherein the secondadvertising channel set is updated to additionally include at least oneadvertising channel in addition to the three advertising channelsconstituting the first advertising channel set.
 13. The device of claim12, wherein the control message further comprises at least one of indexinformation of the additionally included advertising channel, or numberinformation of the advertising channels included in the secondadvertising channel set.
 14. The device of claim 11, wherein the secondadvertising channel set is updated to replace the advertising channel inwhich interference exists with a specific channel among data channelsused for transmitting and receiving data.
 15. The device of claim 14,wherein the control message further comprises at least one of indexinformation of the advertising channel in which interference exists, orindex information of the replacing specific channel.